Why is the "stormtroopers were ordered to let them go" in ANH a "fan theory"?

I find it quite annoying how people seem to think Stormtroopers actually can't hit anything in the original movies based on what happens on the Deathstar. What's even worse though is how it seems a lot of people say there's a "fan theory" that the Stormtroopers were ordered to miss and let them go. How is it a "fan theory" when the movie even says that's what happened?Leia and Han talk about it after escaping, which includes the lines: "They let us go. It was the only reason for the ease of our escape." .... "They're tracking us. "That scene is followed by a scene with Vader and Tarkin, where Tarkin says "You're sure the homing beacon is secure aboard their ship? I'm taking an awful risk, Vader. This had better work."The movie outright confirms without a doubt that they were let go, but somehow it's refered to a lot of the time as a "fan theory" as if it's just something fans came up with and it might not be true. Why? Calling it a "fan theory" seems based entirely on people being ignorant of what's stated in the movie. via /r/StarWars http://ift.tt/2g3UpG3